title: Planar coupling to high-Q lithium niobate disk resonators.
abstract: We demonstrate optical coupling to high-Q lithium niobate disks from an integrated lithium niobate waveguide. The waveguides are made by proton exchange in X-cut lithium niobate substrate. The disks with diameter of 4.7 mm and thickness of 1 mm are made from commercial Z-cut lithium niobate wafers by polishing the edges into a spheroidal profile. Both resonance linewidth and cavity ringdown measurements were performed to calculate the Q factor of the resonator, which is in excess of 10(8). Planar coupling represents the most promising technique for practical applications of whispering gallery mode resonators.
authors.affiliation: NelloCarrara Institute of Applied Physics, IFAC-CNR, Via Madonna del Piano 10, 50019 Sesto Fiorentino, Firenze, Italy. g.nunziconti@ifac.cnr.it
authors.forename: G
authors.initials: G
authors.lastname: Nunzi Conti
authors.forename: S
authors.initials: S
authors.lastname: Berneschi
authors.forename: F
authors.initials: F
authors.lastname: Cosi
authors.forename: S
authors.initials: S
authors.lastname: Pelli
authors.forename: S
authors.initials: S
authors.lastname: Soria
authors.forename: G C
authors.initials: GC
authors.lastname: Righini
authors.forename: M
authors.initials: M
authors.lastname: Dispenza
authors.forename: A
authors.initials: A
authors.lastname: Secchi